1. Technical Field
It relates to a method for preparing metal nanoparticles using a metal seed and metal nanoparticles including a metal seed.
2. Description of the Related Art
Chemical method, mechanical method and electrical method can be employed to produce gold nanoparticles. It is difficult to provide high pure particles due to impurities and to form uniform size of particles with the mechanical method using mechanical force to grind particles. The electrical method have some drawbacks such as a long period of manufacturing time and low yield. The chemical method can be divided to a vapor-phase method and a liquid-phase method. The vapor-phase method using plasma or vaporation requires use of expensive equipments. Thus, the liquid-phase method has been used widely to prepare uniform-sized particles in low production cost.
A well-known method for manufacturing gold nanoparticles is a non-aqueous method using thiol as a surfactant. This method allows the formation of uniform-sized gold nanoparticles but requires using of reducing agents and/or phase change materials which are environmentally unfriendly and costly. Further, thiol materials on the surface of particles cannot be easily removed and thus the particles may not be suitable for conductive inks.
On the other hand, typical aqueous methods, which are chloroauric acid (HAuCl4) reduction in water which uses citric acid and chloroauric acid reduction using sodium borohydride (NaBH4), provide uniform-sized nanoparticles. However, production yield is low so that they may not be suitable for mass production and even if particles are mass-produced, the dispersion stability is significantly decreased in high concentration of solutions.
In addition, methods for manufacturing gold nanoparticles using UV, NIR (near infrared ray), ultrasonics wave and microwave have been introduced but they still have problems of low production yield, production scale, ununiform energy transmission, etc to be solved.